使用子组件中的方法和计算属性

<!-- 子组件 -->
<template>
  <button @click="handleClick">点击按钮</button>
</template>

<script>
export default {
  methods: {
    handleClick() {
      this.$emit('custom-event', 'Hello World');
    }
  }
}
</script>

<!-- 父组件 -->
<template>
  <div>
    <child-component @custom-event="handleCustomEvent"></child-component>
    <p>{{ message }}</p>
  </div>
</template>

<script>
import ChildComponent from './ChildComponent.vue';

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      message: ''
    }
  },
  methods: {
    handleCustomEvent(data) {
      this.message = data;
    }
  }
}
</script>

<!-- 子组件 -->
<template>
  <div>{{ parentMessage }}</div>
</template>

<script>
export default {
  computed: {
    parentMessage() {
      return this.$parent.message;
    }
  }
}
</script>